Reeling mechanism



Oct. 8, 1946. v w. P. LEAR 2,409,132

REELING MECHANISM Filed Oct. 19, 1943 3 Sheets-Sheet l INVENTOR. W/Zl/AM R ZZAR A T TORNEY Oct. 8, 1946. w. P. LEAR 2,409,132

REELING MECHANISM Filed Oct. 19, 1943 3 Sheets-Sheet 2 INVENTOR.

W/Z 1 MM R L 54/? B ATTORNEY O w. P. LEAR 2,409,132

REELING HECHANI SM Filed Oct. 19, 1943 Sheets-Sheet 3 97, ,w V// ,A

I IN VEN TOR. W/AZ MM P. A [AR AT TOR Patented Oct. 8, 1946 REELING MECHANISM William P. Lear, North Hollywood, Calif" assignor, by mesne assignments, to. Lear, Incorporated, Grand Rapids, Mich., a corporation of Illinois Application October 19, 1943, Serial No. 506,796

9 Claims.

This invention relates to novel mechanical actuator devices, and more particularly to mechemically and manually actuable apparatus for extending and retracting the landing hook of a carrier based airplane.

The invention is particularly directed to an actuator for moving a member between a pair of limiting points, with means for stopping motion of the actuator when the member reaches either of the limiting points. Hitherto, this has generally been accomplished by means of electric limit switches which require skilled and accurate, setting in order to insure proper functioning at the exact limiting point. In case of any improper setting of the limit switches, damage to the elements of the actuator might occur from shock or impact due to the member overrun-ning the limiting points. With the present invention, a device is provided which automatically stops motion of the actuator when the movable member reaches either limiting point, through the increased torque exerted by the actuator power drive means by reason of the member reaching such limiting point.

The invention is capable of general application, but is more particularly applicable to a rotary actuator for operating the arresting gear or landing hook of carrier based aircraft. Carrier based military aircraft are generally equipped with arresting gear, such as. an extendible hook, which, when the aircraft is landing on the deck of a carrier is adapted to grip a suitable landing device, such as a cable, to rapidly arrest forward motion of the aircraft on the deck. Such provision is generally necessary in view of the relatively high landing speeds of such military aircraft, as compared with the relatively short length of the flight deck.

It is among the objects of this invention to provide mechanism for moving a member between a pair of limiting points and including a device automatically efiective when the movable member reaches either of such points to stop motion to the mechanism; to provide an actuator for moving a member between a pair of limiting,

points, and including an electric motor and a torque responsive device efiective automatically to deenergize said. motor when the movable member reaches either of the limiting points; to provide a rotary actuator for extending and retract-. .ing the landing hook of an aircraft;- to provide such a mechanism including power drive means, such as an electric motor, for operating the same; to provide such a mechanism including a novel torque limiting arrangement for efiecting deenergization of the power drive means at either extreme position of the landing hook to avoid.

destruction by impact; to provide such a mecha nism including a manually operable device, normally' disconnected from the mechanism, but effective upon actuation of the device to becon nected, to the mechanism to extend the landing hook; to provide. such a mechanism including power drive means and manual drive means to permit foolproof extension, of the hook, both controllable from a position adjacent the pilots seat; and. to provide a simple reliable arresting gear actuator for an airplane.

These. and other objects, advantagesv and features of the invention will be apparent from the following description and accompanying draw ings. In the drawings:

Fig. l is a schematic elevation, partly broken away, of an airplane equipped with the hook operating mechanism of the present invention.

Fig- 2- is a longitudinal sectional view through mechanism embodying the principles of the present invention.

Fig. 3 is a cross-sectional view on the line 3--3 of Fig. 2.

Fig. 4 is. a cross-sectional view on the line 4-4 0f Fig. 2.

Fig. 5 is a cross-sectional view on the line 5--5 of Fig. 2.

Fig. 6 is a cross-sectional view on, the line 6-6 of Fig. 2.

Fig. 7 is a schematic wiring diagram illustrating the electrical connections for controlling the operation of the rotary actuator of the invention.

Referring to the drawings, and particularly to Fig. 1 thereof, an airplane in is shown as equipped with a landing hook shown in the extended position at I5 and in dotted lines in the retracted position at I5. The mechanism for extending and retracting the hook comprises a pair. of sprockets H and I2 interconnected by suitable means such as an endless chain [4. A rotary actuator 20, shown more particularly in Figs. 2 5 and 6, is connected to the sprocket l l. A power drive means is provided for actuator 20, and may be an electric motor which is controlled from a position adjacent the pilots seat by a pair of push buttons 18 and I1. Conductors l8 connects the push buttonsto control box illustrated diagrammatically at 22. Leads 23 connect the control box 22 to the electric motor associated with the actuator.

It is important to provide for manual actuation in the event of Iailure of the power drive 3 means, to insure lowering of the hook at all times during a landing operation. For this purpose a cable 26 extends from a manual actuating device associated with actuator 20 to a point adjacent the pilots seat. Cable 26 may extend through a bracket 21 and be provided with a suitable grip 28. Upon actuation of one of the push buttons l6 or H, hook I5 is either extended or retracted. In the event of failure of the power drive means, the pilot may grasp grip 28 and by pulling the same forwardly and releasing the same a sufll cient number of times, may extend hook IS in a manner to be described more fully hereinafter thus assuring positive lowering of the hook during all landing operations. 1

Actuator 20 is shown in longitudinal sectional view in Fig. 2. It comprises anelectric motor 38 adapted to be connected through electromag netic clutch 35 to a torque limiting device 4!]. Torque limitin device 40 is connected through reduction gearing 45 to sprocket II. A manual driving device 58, which is operated by cable 26, is adapted to be connected to sprocket II, for extending cable 26, in a manner to be described more fully hereinafter. Electromagnetic clutch 35 may be a quick acting clutch of the type described and claimed in my Patent No. 2,267,114, and torque limiting device 40 may be of the type described and claimed in my copending application Serial No. 499,010.

Clutch 35 includes a driving disk 3i of magnetic material secured to armature shaft 32 of motor 30 and containing a non-magnetic ring 2|. A driven disk 33,'likewise of magnetic material, is arranged adjacent driving disk 3|. A suitable magnetizing winding 34 is provided in the clutch housing, and may be connected in either series or parallel circuit arrangement with motor 30. Upon energization of winding 34, driven disk 33 is simultaneously urged into magnetic and frictional coaction with driving disk 3|, so that armature shaft 32 is effective to rotate pinion 36 formed integrally with disk 33. Upon deenergization of winding 34, a spring 3! instantaneously snaps disk 33 into engagement with a brakin surface 38, to substantially instantaneously arrest motion of pinion 36 and actuator 28 at the desired position.

Pinion 36 cooperates with torque limitin device 48. As shown in Figs. 2, 3 and 4, pinion 36 meshes with a plurality of planetary gears 4i rotatably mounted on a movable mounting plate 42. Pinions 43 are secured to gears 4i and mesh with an internal ring gear 44 rotatably mounted on bearings46in a housing 41. A plate 48 is provided to support the forward ends of the shafts 5| on which gears 4| and pinions 43 are mounted. Ring gear 44 is provided with a hub 52 terminating in a drive pinion 53.

Referring to Fig. 3, movable mounting member 42 is provided with gear teeth 54 disposed adjacent an opening 55 in housing 41. Teeth 54 mesh with teeth 56 of a sector 51. Sector 51 is mounted on a sleeve 58, disposed on a longitudinally adjustable shaft 60 mounted in one wall 6| of a switch housing 62 secured to housing 41. The opposite end of shaft 60 is mounted in an upstanding ear 63 formed integrally with housing 62. A nut 64 is provided for adjusting shaft '60 longitudinally, the shaft and the sector 51 "68'and I engage adjustable seats H and 12, the

position of which may be adjustable by screws 13 and 14 provided with lock nuts and 16. On

the upper end of sector 51 is a suitable operating means such as a roller '1! which cooperates 5 with push buttons 18 and 88 of a pair of switches 8| and 82 mounted in housin 62. Leads 23 are brought into housing 62 through an entrance bushing 19.

As explained in my copending application Serial No. 499,010, sector 51 is normally maintained in a position midway between push buttons 18 and 88. Springs 68 and normally restrain movement of the sector and of movable plate 42. However, when the torque upon the driven system exceeds a preselected value, plate 42 and sector 5! are moved in one direction or the other to open one of the switches 8! or 82 and thus deenergize motor and instantaneously declutch the motor armature from the actuator. Adjustment of screws 13 and 14 predetermines the torque required to cause sector 5'! to operate switches 81 or 82.

Referring to Fig. 5,drive pinion 53 engages a spur gear 83 to which is secured a pinion 84 meshing with a spur gear 85. Pinion 86 fixed to spur gear 85 meshes with a driving spur gear 81. Gear 81 is keyed to a shaft 88 having a reduced portion 98 mounted in bearings Si in a housing 92 enclosing the gearing. The opposite end of shaft 88 is mounted in bearings 93 and is provided with a recess 84 for a purpose to be described hereinafter. A collar 86 maintains bearings 93 and spur gear 8'! in proper relation. Drive sprocket i I is keyed to shaft 88.

Upon depression of one of the push buttons 46 or IT, motor 30 and clutch are energized to drive sprocket H through torque limiting device and reduction gearing 45. Hook I5 is either extended or retracted, dependent upon which push button is operated. Upon hook l5 reaching either limit of its movement, the torque exerted by motor 30 willbe such as to cause movement of plate 42 in one direction or the other. This will accordingly open one of the switches 8| or 82 to deenerglze motor 30. Clutch 35 is cleanergized simultaneously therewith, whereupon spring 31 snaps disk 33 into engagement with brake surface 38. This substantially instantaneously stops motion of sprocket I l.

The torque limiting device 48 avoids the use of electric limit or stop switches which require skilled and accurate mounting and adjustment. Additionally, it insures foolproof operation of the mechanism with positive stopping thereof at the limits of operation, thus avoiding damage to the apparatus. The electrical disconnection of the motor 30 through the clutch 35, promptly mechanically disconnects the stored rotative energy of the motor armature from the actuator 28 in time to avoid breakage of mechanical components such as gearing by impact due to the hook l5 being drawn past its fully retracted or extended positions. I

' Should the electrical supply or the motor 30 fail, there is still an urgent need for extending the hook for landing operation. For this reason,

the manual operating device 50 is provided to extend the hook. This device is designed to substantially reduce the torque to be supplied by hand for extending the hook. Manual driving device 50 is mounted in a bracket 81 secured to gear housing 92. Device 50 includes a cupshaped bracket 98 secured to the forward wall of the bracket 91. Bracket 88 supports a shaft I00 having a reduced portion IDI inserted in a sleeve stop I23.

I02 set in recess 94. A boltr '15 and lock nut I06 are provided for proper adjustment of shaft I00. Fitted on shaft I with a driving fit is a drum I01 provided with a helical groove I08 adapted to receive cable 26. A spring I I0 is secured at one end to drum I01 and at its opposite end to a cup-shaped member Hi8 secured to bracket 98 by pins I I0.

Sprocket II is formed with a hub portion III provided with ratchet teeth II2. A pawl II3 mounted on drum I01 has an end II4 normally urged toward engagement with teeth H2 by a leaf spring H5. However, spring III) normally urges drum I01 to a position wherein a roller Hi I} on the opposite end of pawl I I3 is engaged by a cam III secured to the upper wall II8 of bracket 91. Cam II! is provided with a sloping surface I20 which engages roller I I and forces it against a stop I2I. This moves end II4 of pawl H3 out of engagement with teeth I I2.

One end of cable 26 extends through an aperture I22 in drum I01 and has secured thereto a The other end of the cable extends outwardly from bracket 91 to a position adjacent the pilots seat, as explained heretofore. When the pilot grasps grip 28 and pulls cable 28 outwardly, drum I0! is rotated and spring III) is wound up. Such actuation of cable 26 moves the drum in a counter clock-wise direction. Upon the start of such movement, pawl H3 is disengaged from cam II! and end II4 of the pawl engages teeth II2. This connects drum I01 to sprocket II to move chain I4 in a direction to extend hook I5. After a little less than one revolution, pawl H3 engages the opposite side of cam II'I, stopping rotation of the drum. The pilot then releases cable 26 and spring IIO rotates drum I 01 back to its original position. During such reverse rotation, pawl I I3 slides over teeth II2 leaving the sprocket II in its operated position. The pilot again grasps grip 28 and pulls cable 26 outwardly. This operation is repeated until such time as hook I5 is fully extended.

A preferred control circuit arrangement for the device of the present invention. is schematically,

illustrated in Fig. 7. As shown in this figure, motor 30 is adapted to be energized through the medium of push buttons I6 and I1. 015 these push button I6 may be considered the in button, and push button I! the out" button. Upon depression of button I6, its contacts close a circuit through a relay I25. Relay I25, through its upper armature I25, closes a circuit for motor 30 through torque limit switch 82 and motor field winding I21. Field I21 is so arranged that it will cause motor 30 to operate in a, direction to retract hook I5 into the fuselage of aircraft III. When the hook has been fully retracted into the aircraft, the increased torque exerted upon the motor will cause arm 51 to contact push button 80 and thus open switch 82. Push button I 5 need be depressed only momentarily, as relay I25 completes a holding circuit through its lower armature I28.

Depression of out push button I! energizes a relay I30 which attracts its armature I3I to energize motor 36 through field winding I32, in such a direction as to cause hook !5 to be extended. At the same time, relay I30 closes a holding circuit for itself through its armature !33. A warning light I35 is lighted to indicate extension of hook I5. Motor 39 continues to operate until the hook is substantially fully extended. At such time, the increased torque exerted on the motor will cause arm 51 to move its roller 11 into engagement with push button 18. This will move switch 8| to a position opening the circuit through motor 30. At the same time, switch 8| will engage a contact I34 closing a parallel circuit for maintaining lighted a warning light I which indicates to the pilot that the hook is extended.

While a specific embodiment of the invention has been shown and described for the purpose of illustrating the application of the principles thereof, it will be obvious to those skilled in the art that the invention may be otherwise embodied without departing from such principles.

What is claimed is:

l. Extending and retracting mechanism comprising in combination a movable member; an actuator operatively associated with said movable member for extending and retracting the same; a ratchet secured to said actuator; power drive means; a torque limiting device connected to said actuator; means effective upon energization of said power drive means to connect the same to said torque limiting device to extend or retract said movable member, said torque limiting device having circuit means efiective to deenergize said power drive means when the torque on said actuator exceeds a preselected value; a reel; a bracket supporting said reel; a cable secured to said reel to rotate the same in one direction; a grip secured to said cable; means urging said reel to rotate in the opposite direction to rewind said cable thereon; means urging said pawl into engagement with said ratchet to interconnect said reel and said actuator; and a cam secured to said bracket and adapted to engage said pawl to release the same from said ratchet when said cable is rewound on said reel.

2. Extending and retracting mechanism comprising in combination a movable member; an actuator operatively associated with said movable member for extending and retracting the same; a ratchet secured to said actuator; an electric motor; a torque limiting device connected to said actuator; means effective upon energization of said electric motor to connect the same to said torque limiting device to extend or retract said movable member, said torque limiting device having circuit means efiective to deenergize said electric motor when the torque on said actuator exceeds a preselected value; a reel; a bracket supporting said reel; a cable secured to said reel to rotate the same in one direction; a grip secured to said cable; means urging said reel to rotate in the opposite direction to rewind said cable thereon; means urging said pawl into engagement with said ratchet to interconnect said reel and said actuator; and a cam secured to said bracket and adapted to engage said pawl to release the same from said ratchet when said cable is rewound on said reel.

3. Extending and retracting mechanism comprising in combination a movable member; an actuator operatively associated with said movable member for extending and retracting the same; a ratchet secured to said actuator; an electrio motor; a torque limiting device connected to said actuator; electromagnetic clutch means effective upon energization of said electric motor to connect the same to said torque limiting device to extend or retract said movable member, said torque limitin device having circuit means effective todeenergize said electric motor when the torque on said actuator exceeds a preselected value; a reel; a bracket supporting said reel; a

cable secured to said reel to rotate the same in one direction; a grip secured to said cable; means urging said reel to rotate in the opposite direction to rewind said cable thereon; means urging said pawl into engagement with said ratchet to interconnect said reel and said actuator; and a cam secured to said bracket and adapted to engage said pawl to release the same from said ratchet when said cable is rewound on said reel.

4. An aircraft arresting gear operator comprising, in combination, a pair of sprockets; mechanism interconnecting said sprockets; arresting gear secured to said mechanism; a torque limiting device connected to one of said sprockets; a ratchet secured to said one sprocket; power drive means; clutch means effective upon energization of said power drive means to connect the same to said torque limiting device to extend or retract said arresting gear; a reel; a bracket supporting said reel; a cable secured to said reel to rotate the same in one direction; a grip secured to said cable; means urging said reel to rotate in the opposite direction to rewind said cable thereon; means urging said pawl into engagement with said ratchet to interconnect said reel and said one sprocket; and a cam secured to said bracket and adapted to engage said pawl to release the same from said ratchet when said cable is rewound on said reel.

5. An aircraft landing hook operator comprising, in combination, a, pair of sprockets; endless means interconnecting said sprockets; a landing hook secured to said endless means; a torque limiting device connected to one of said sprockets; a ratchet secured to said sprocket; an electric motor; electromagnetic clutch means effective upon energization of said electric motor to connect the same to said torque limiting device to extend or retract said landing hook; a reel; a bracket supporting said reel; a cable secured to said reel to rotate the same in One direction; a grip secured to said cable; means urging said reel to rotate in the opposite direction to rewind said cable thereon; means urging said pawl into engagement with said ratchet to interconnect said reel and said one sprocket; and a cam secured to said bracket and adapted to engage said pawl to release the same from said ratchet when said cable is rewound on said reel.

6. An aircraft landing hook operator comprising, in combination, a pair of sprockets; a chain interconnecting said sprockets; a landing hook secured to said chain; a ratchet secured to one .of said sprockets; reduction gearing connected to said one sprocket; an electric motor; planetary gearing, said planetary gearing including an element coupled to said reduction gearing, a movable mounting plate and an element adapted to be coupled to said electric motor; an electromagnetic clutch effective upon energization of said electric motor to connect the same to said last named element to extend or retract said landing hook; a pair of switches interposed in the circuit of said electric motor; an actuatin member disposed in operative relation with said switches, said actuating member being operable by said mounting plate to selectively open said switches to deenergize said electric motor and clutch when the torque of said motor exceeds a preselected ,value; means normally restraining movement of said mounting plate and said actuating member; a reel; a bracket supporting said reel; a cable secured to said reel to rotate the same in one direction; a, grip secured to said cable; means urgin g said reel to rotate in the opposite direction to rewind said cable thereon; a pawl mounted on said reel adjacent said ratchet; means urging said pawl into engagement with said ratchet to interconnect said reel and said one sprocket; and a cam secured to said bracket and adapted to engage said pawl to release the same from said ratchet when said cable is rewound on said reel.

'7. In combination, an aircraft having a fuselage; a landing hook adapted to be extended from and retracted into said fuselage; a first sprocket located adjacent the midsection of said fuselage; a second sprocket located adjacent the rear section of said fuselage; an endless chain engaging said sprockets; means securing said hook to said chain; a ratchet secured to said first sprocket; an electric motor; a torque limiting device connected to said first sprocket; clutch means effective upon energization of said electric motor to connect the same to said torque limiting device to extend or retract said landing hook; a reel; a bracket supporting said reel; a cable secured to said reel to rotate the same in one direction; a grip secured to said cable; means urging said reel to rotate in the opposite direction to rewind said cable thereon; means urging said pawl into engagement with said ratchet to interconnect said reel and said first sprocket; and a cam secured to said bracket and adapted to engage said pawl to release the same from said ratchet when said cable is rewound on said reel.

8. In combination, an aircraft having a fuselage; a landing hook adapted to be extended from and retracted into said fuselage; a first sprocket located adjacent the mid-section of said fuselage; a second sprocket located adjacent the rear section of said fuselage; an endless chain engaging said sprockets; means securing said hook to said chain; an electric motor; a torque limiting device connected to said first sprocket; clutch means effective upon energization of said electric motor to connect the same to said torque limiting device to extend or retract said landing hook; a reel; a bracket supporting said reel; a cable secured to said reel to rotate the same in one direction; a grip secured to said cable; means urging said reel to rotate in the opposite direction to rewind said cable thereon; a ratchet secured to said first sprocket; a pawl mounted on said reel adjacent said ratchet; means urging said pawl into engagement with said ratchet to interconnect said reel and said one sprocket; and a cam secured to said bracket and adapted to engage said pawl to disengage the same from said ratchet.

9. In combination, an aircraft having a fuselage; a landing hook adapted to be extended from and retracted into said fuselage; a first sprocket located adjacent the mid-section of said fuselage; a second sprocket located adjacent the rear section of said fuselage; an endless chain engaging said sprockets; an electric motor; reduction gearing connected to said one sprocket; planetary gearing, said planetary gearing including an element coupled to said reduction gearing, a movable mounting plate and an element adapted to be coupled to said electric motor; means effective upon energization of said electric motor to connect said motor to said last named element; a pair of switches interposed in the circuit of said electric motor; an actuating member disposed in operative relation with said switches, said actuating member being operable by said mounting plate to selectively open said switches to deenergize said electric motor when the torque of said motor exceeds a preselected value; means nor- 9 mally restraining movement of said mounting plate and said actuating member; a reel; a bracket supporting said reel; a cable secured to said reel to rotate the same in one direction; a grip secured to said cable; means urging said reel to rotate in the opposite direction to rewind said cable thereon; a ratchet secured to said first 10 sprocket; a pawl mounted on said reel adjacent said ratchet; means urging said pawl into engagement with said ratchet to interconnect said reel and said one sprocket; and a cam secured to said bracket and adapted to engage said pawl to disengage the same from said ratchet.

WILLIAM P. LEAR. 

